Earth Research Institute, University of California, Santa Barbara , CA 93106, USA.
Environ Sci Technol. 2011 Feb 15;45(4):1659-64. doi: 10.1021/es103040t. Epub 2011 Jan 5.
Increased use of engineered nanoparticles (ENPs) raises concerns about their environmental impacts, but the effects of metal oxide ENPs on environmental processes and the organisms that carry them out remain largely unknown. This study evaluated the impacts of TiO2 and ZnO ENPs on soil bacterial communities. Soils collected from a California grassland were exposed to different doses of nanoparticulate TiO2 (0, 0.5, 1.0, and 2.0 mg g(-1) soil) and ZnO (0.05, 0.1, and 0.5 mg g(-1) soil) in microcosms over 60 days. The effects on soil microbial biomass were assessed by substrate induced respiration (SIR) and total extractable soil DNA. The effects on bacterial community composition were evaluated by terminal restriction fragment length polymorphism (T-RFLP) analysis. Total soil respiration indicated impacts on overall microbial activity. We found that both nano-TiO2 and nano-ZnO reduced both microbial biomass (as indicated by declines in both SIR and DNA) and diversity (by T-RFLP). Both types of nanoparticles also altered the composition of the soil bacterial community. The effect of nano-ZnO was stronger than that of nano-TiO2, as reflected by lower DNA and stronger shifts in bacterial community composition for nano-ZnO at the same exposure concentration (0.5 mg g(-1) soil). Thus, nanoparticulate metal oxides may measurably and negatively impact soil bacterial communities.
纳米技术的广泛应用引起了人们对其环境影响的关注，但是金属氧化物纳米颗粒对环境过程和携带它们的生物体的影响在很大程度上仍然未知。本研究评估了 TiO2 和 ZnO 纳米颗粒对土壤细菌群落的影响。从加利福尼亚草原采集的土壤在微环境中暴露于不同剂量的纳米 TiO2（0、0.5、1.0 和 2.0mg g-1 土壤）和 ZnO（0.05、0.1 和 0.5mg g-1 土壤）60 天。通过基质诱导呼吸（SIR）和总可提取土壤 DNA 评估对土壤微生物生物量的影响。通过末端限制性片段长度多态性（T-RFLP）分析评估对细菌群落组成的影响。总土壤呼吸表明对整体微生物活性有影响。我们发现纳米 TiO2 和纳米 ZnO 都降低了微生物生物量（SIR 和 DNA 下降表明）和多样性（通过 T-RFLP 表明）。两种类型的纳米颗粒还改变了土壤细菌群落的组成。纳米 ZnO 的影响比纳米 TiO2 强，因为在相同的暴露浓度（0.5mg g-1 土壤）下，纳米 ZnO 的 DNA 更低，细菌群落组成的变化更强。因此，纳米颗粒金属氧化物可能会对土壤细菌群落产生可测量的负面影响。
